Conventionally, in order to achieve a high level of automated operation in a plant, a factory, or the like, a distributed control system (DSC) has been implemented, in which on-site devices such as measuring instruments and actuators, which are referred to as field devices are connected via a communication means to controllers that controls the field devices. Although the communication system that forms the base of such a distributed control system had been almost always one that communicates by cable, recent years have seen the appearance of ones that communicate wirelessly, in conformance with an industrial communication standard such as ISA100.11a or WirelessHART (registered trademark).
The above-noted ISA100 is a wireless communication standard used in measurement, control, or the like in a plant or the like and was established by the ISA (International Society of Automation). In contrast, the above-noted WirelessHART is a wireless communication standard put forward by the HART (Highway Addressable Remote Transducer) Communication Foundation in the US as the base of a sensor network (a wireless network enabling collection of environmental or physical conditions by wireless terminals having a plurality of sensors spatially distributed and acting in concert).
In Patent Reference 1 noted below, art is disclosed that mutually connects a wireless sensor network conforming to ZigBee (registered trademark), which is a wireless standard for near-field and low-power consumption communication, and an IP network, which is a network of computers mutually connected using the IP (Internet Protocol). Specifically, in Patent Reference 1 noted below, by providing a gateway having a protocol stack implementing communication via a wireless sensor network conforming to ZigBee and a protocol stack implementing communication via the IP network, these networks are mutually connected.